The present invention generally relates to the adjustment of optical assemblies and, in particular, relates to a mechanism for rotating two optical assemblies about a common axis, one at twice the angular speed of the other, through the use of a parallel action joint lever system.
The use of microscopes, telescopes, and other optical assemblies is presently widespread and is expanding due to advances in optical technology. The users of such optical assemblies typically must spend a considerable amount of time peering through an eyepiece that is attached to the optical assembly. The position of the eyepiece with respect to the position of a particular user varies depending upon the type of optical assembly being used, the location where the optical assembly is situated, and the size of the particular user. To provide a user with a comfortable viewing position, many optical assemblies are comprised of some sort of means for adjusting the position of the eyepiece with respect to the position of the user.
To date, the position of an eyepiece of an optical assembly has typically been adjusted through the use of a series of gears. Such gears are rotatably mounted to the optical assembly so as to allow the eyepiece to move in a precise manner with respect to the rest of the optical assembly. These gears must be accurately machined and fitted so as to allow such precise eyepiece movement without significantly affecting the imaging of the optical assembly, or causing optical image shifts. The machining and fitting processes are painstakingly tedious and, even when considerable care is given to these processes, backlash problems can still occur if the gears become loosely engaged due to any depreciative effects on the gear teeth over time or due to debris becoming caught between the gear teeth.
To overcome the above-mentioned shortcomings associated with using a series of gears to adjust the position of an eyepiece of an optical assembly, emphasis must be placed on manufacturing a suitable replacement at low cost. Otherwise, a high cost solution to overcome the above-mentioned shortcomings would reap no benefits in a competitive marketplace. It would therefore be desirable to overcome the shortcomings of the above-mentioned prior art adjustment means, while providing a simple, low cost mechanism for precisely adjusting the eyepiece of an optical assembly without causing optical image shifts.